Brake



Jan. 11, 1938. L. E. LA BRIE 2,105,046

BRAKE Filed April 30, 1935 2 SheetS-Shet 1 IN VEN TOR. loosen E. Lnbmr:`BY l Jn. 11, 1938. E LA BRlE 2,105,046

BRAKE Filed April 30, 1935 2 Sheets-Sheet 2 INVENTOR. Lucena E. Lnmr BYPatented jan. il, i938 idtt )BRAKE Ludger E. La Brie, South Bend, Ind.,assigner to Bendix Products Corporation, South Bend, lind., acorporation of Indiana Application April 30,

`1o claims.

This invention relates to brakes, and is illustrated as embodied in aninternal expanding automobile brake. An object of the invention is topreserve the uniformity of action and the great controllability of ananchored shoe brake, while increasing its eiectiveness by applying addedpressure to the unwrapping shoe.

In one desirable arrangement, one of the shoes (e. g. theunwrapping`shoe, which tends in forward braking to be swung away fromthe drum by the wiping action of the rotating drum) is mounted at oneend on a fixed anchor, preferably a fixed pivot or anchor post. Theother shoe is connected to the anchored shoe, near its an- ]0 choredend, by means such as a rigid link, ar-

ranged to act at such an angle as to urge the anchored shoe outwardlytoward the drum in opposition to the unwrapping action of the drum.

An important feature of the invention relates to the use, in combinationwith shoes so arranged and connected, of an applying device which exertsa constant balanced pressure on the two shoes in spite of the fact thatone of them merely swings about its anchor while the other is movedbodily by the drumfriction to exert a pressure upon the above-describedlink. I prefer to use a hydraulic applying device, for example acylinder containing opposed pistons shown as having means such as thrustrods connecting them to the respective shoes.

At least the thrust rod acting on the unanchored shoe may swing across`its center posi- Vtion in moving from brake-released to brakeappliedposition, thereby minimizing the piston travel corresponding to a givenshoe movement.

The link described above may, if desired, be clamped frictionally to theunanchored shoe, so that it can adjust its position automatically underpressure.

The above and other objects and features of the invention, includingvarious novel combinations and desirable particular constructions, willbe apparent from the'following description of the illustrativeembodiments shown in the accompanying drawings, in-which:

Figure 1 is a section vertically through, the brake, just inside thehead of the brake drum, showing the shoes in side elevation;

Figure 2 is a section on the line 2-2 of Figure 1, showing theconnection between the shoes; and

Figures 3, 4 and 5'are sections corresponding to Figure l, but showingdifferent modied arrangements.

In the arrangement of Figures 1 and 2, the

1935, Serial No. 19,074

(Cl. 18S-152) side of which is a support such as a backing plate I2shown as cooperating with the drum to form a substantially closedhousing for the brake shoes.

The friction means of the brake includes a reverse or secondary shoe I4anchored at its lower end on a pivot such as an anchor post I6 carriedby the backing plate. The wiping or wedging action of the drum inforward braking, i. e. with the drum turning counterclockwise, tends toswing this shoe I4 away from the drum about the pivot I6, and one objectof the invention is to increase the effectiveness of this shoe or itsequivalent in forward braking.

The forward or primary shoe, indicated at I8, in this embodiment isconnected to a pivot 20 carried by the web of shoe I4 radially somedistance inwardly of the anchor I6, by means such as a pair `of links 22embracing the webs of the shoes between them, and connected to shoe I8by a pivot 24. The pivot 24 is shown riveted over at its ends to holdtensioned a pair of friction washers 26 gripping the opposite sides ofthe web of shoe I8. This normally holds the links 22 frictionallygripped to shoe I8, while however they can yield with respect theretounder pressure so that the shoe can automatically adjust its position.The adjustment takes place when the shoe is applied, since the link 22will assume a certain position relative to the shoe as the braking forceAovercomes the friction at pivot 24 and the shoe engages the drum overits whole surface. When the shoe is retracted it swings as a unit aboutpivot 20 as no forces are exerted sufficient to shift the pivot 24. Asthe shoe lining wears, the link will assume successive new positionsautomatically determined by the position of the shoe when engaged withthe drum.

The shoes are urged' yieldingly away from the drum by a release spring28 tensioned between the shoes, to released positions determined byadjustable eccentric stops 30 engageable with the rims of the shoes. Thebrake is applied by means which exerts balanced pressures at all times,even though shoe I4 merely swings on the anchor pivot I6 While shoe I8has a limited bodily' movement downward. This means is illustrated as ahydraulic actuator, including a cylinder 32 rigidly attached to thebacking plate I2 and within which are opposed pistons 34 (Figure 3)recessed for pivotal engagement with the rounded ends of thrust rods 36slotted at their outer ends to embrace and engage the ends of theshoewebs. The cylinder is positioned angularly so that it exerts applyingforce downwardly on shoe iii inppposition to the friction force of theshoe when the brake is applied in reverm. This prevents backing od theautomatic adjustment at pivot it.

In Figure 3, reverse shoe lid anchored on a pivot lit is connected bylinks lit/to the lower end of a relatively short primary shoe llt. Thelinks 022 are in this case positioned in released position by anadjustable eccentric stop i3d. AB shown in this ilgure, the thrust rodstt which engage the primary shoe il@ may be arranged to swing past acenter position aligned with the anis of cylinder 32 in passing frombrake-released to brake-applied position, thereby minimizing themovement of the piston 3d in applying the brake.

In Figure 4, a relatively long primary shoe 20d is connected a shortIdistance below its center by links 222 to the reverse shoe 2M. InFigure' 5 a shorter primary shoe 3l@ Vis connected just below thehorizontal diameter o the if. :u by links 322 connected to shoe 3 llivery close to the anchor dit. i,

it will be appreciated that the diii'erent lengths of primary shoes givedifferent characteristics ci operation, especially as to lining wear,whereas the force transmitted to the secondary shoe is modied by theangle of the connecting links as well as by the points at which they areconnected to the shoes.

While several embodiments have been described in detail, it is not myintention to limit the scope of the invention to those particularembodiments, or otherwise than by the terms of the appended claims.

I claim:

1. A brake comprising a pair of generally semicircular shoes one ofwhich has an anchor atl one end and the otherof which is unanchored,

said shoes being so arranged that the unanchored shoe is self-actuatingin forward braking, a link directly connecting the adjacent part of theunanchored shoe to the anchored shoe adjacent said anchonand an applyingdevice acting on the ends of said shoes opposite the anchor and which lsconstructed and arranged to apply a balanced spreading pressure on saidshoes while the anchored shoe swings on its anchor and the other shoemoves bodily to apply pressure through said link to the anchored shoe.

2. A brake comprising a. pair of generally semi circular shoes one ofwhich has an anchor at one end and the other of which is unanchored,said shoes being so arranged that the unanchored shoe is self-actuatingin forward braking, a link directly connecting the adjacent ypart of theunanchored shoe to the anchored shoe adjacent said anchor, said linkbeing connected andfarranged at such an angle that pressure lengthwiseof the link tends to swing the anchored shoe outwardly about saidanchor, and an applying.

device acting on the ends of said shoes gppesite the anchor and which isconstructed and arranged to apply a balanced spreading pressure on saidshoes .while the anchored shoe swings on its anchor and the other shoemoves bodily to apply pressure throughfsald link to the anchored shoe.

3. A brake comprising a pair of generally semicircular shoes one ofwhich has an anchor at one end and the other of which is unanchored,.said shoes being so arranged that the unanchored shoe is self-actuatingin forward braking. a link connecting the'adjacent part of theunanchored shce to the anchored s hoe adjacent said anchor, frictionmeans yieldingly clamping one end of @doodle-t@ the link to theunanchored shoe, and an applying device acting on the ends of said shoesopposite the anchor and which is constructed and arranged to apply abalanced spreading pressure on said shoes while the anchored shoe swingson its anchor and the other shoe moves bodily to apply pressure throughsaid link to the anchored shoe.

e. A brake comprising a pair of generally semicircular shoes one ofwhich has an anchor at one end and the other of which is unanchored,said shoes being so arranged that the unanchored shoe is self-actuatingin forward braking, a link connecting the adjacent part of theunanchored shoe to the anchored shoe adjacent said anchor, said linkbeing connected and arranged at such 'an angle that pressure lengthwiseof the link tends to swing the anchored shoe outwardly about saidanchor, friction means yieldingly clamping one end of the link to theunanchored shoe, and an applying device acting on the ends of said shoesopposite the anchor and which is constructed and arranged to apply abalanced spreading pressure on said shoes while the anchored shoe swingson its anchor and the other shoe moves bodily to apply pressure throughsaid link to the anchored shoe. 5. A brake comprising a pair ofgenerally semicircular shoes one of which has an anchor at one end andthe other of which is unanchored, said shoes being so arranged that theunanchored shoe is self-actuating in forward braking, a link directlyconnectingthe adjacent part of the unanchored shoe to the anchored shoeadjacent said anchor, and an applying device acting on the ends of saidshoes opposite the anchor and which is constructed and arranged to applya balanced spreading pressure on said shoes while circular shoes oneof-whichhas an anchor at one end and the other of which is unanchored.

`said shoes being so arranged that the unanchored.

shoe is self-actuating in forward braking, a link directly connectingthe adjacent part of the unanchored shoe to the anchored shoe adjacentsaid anchor, said link being connected and arranged at such lan anglethat pressure length-` wise of the link tends to swing the anchored shoeoutwardly about vsaid anchor, and an Vapplying device acting on the endsof said shoes opposite the anchor and which is constructed and arrangedto apply a balanced spreading pressure on said shoes while the anchoredshoe swings on its anchor and they other shoe moves bodily to applypressure through said link to the anchored shoe, said applying devicecomprising a hydraulic cylinder andpistons therein actingA on the shoesrespectively and adapted to be forced apart by hydraulic pressure toapply balanced spreading pressure to the shoes.

7. A brake-comprising a pair of generally semianchored shoe to theanchored shoe adjacent said anchor,l and an applying device acting onthe ends of said shoes opposite the anchor and which is constructed andarranged to apply a balanced spreading pressure on said Ashoes While theanchored shoe swings on its anchor and the other shoe moves bodily toapply pressure through said link to the anchored shoe, said applyingdevice comprising a hydraulic cylinder and pistons therein having thrustrods connecting them to the shoes respectively and which pistons areadapted to be forced apart by hydraulic pressure to apply balancedspreading pressure to the shoes. p

8. A brake comprising a pair of generally semicircular shoes one ofwhich has an anchor at one end and the otherI of which is unanchored,said shoes being so arranged that the unanchored shoe is self-actuatingin forward braking, a link directly connecting the adjacent part of theunanchored shoe to the anchored shoe adjacent said anchor, said linkbeing connected and arranged at such an angle that pressure lengthwiseof the link tends to swing the anchored shoe outwardly about saidanchor, and an applying device acting on the ends of said shoes oppositethe anchor and which is constructed and arranged to apply a balancedspreading pressure on said shoes while the anchored shoe swings on itsanchor and the other shoe moves bodily to apply pressure through saidlink to the anchored shoe, said applying device comprising a hydrauliccylinder and pistons therein having thrust rods connecting them to theshoes respectively and which pistons are adapted to be forced apart byhydraulic pressure to apply balanced spreading pressure to the shoes.

9. A brake comprising a pair of generally semicircular shoes one ofwhich has an anchor at one end and the other of which is unanchored.said shoes being so arranged that the unanchored shoe is self-actuatingin forward braking, a link connecting the adjacent part of theunanchored shoe to the anchored shoe adjacent said anchor, and anapplying device acting on the ends of said shoes opposite the anchor andwhich is constructed and arranged to apply a balanced spreading pressureon said shoes while the anchored shoe swings on its anchor and the othershoe moves bodily to apply pressure through said link to the anchoredshoe, said applying device comprising a hydraulic cylinder and pistonstherein having thrust rods connecting them to the shoes respectively andwhich pistons are adapted to be forced apart by hydraulic pressure toapply balanced spreading pressure to the shoes, at least that one ofsaid thrust rods which acts on the unanchored shoe being arranged toswing past its center position in moving from brake-released tobrakeapplied position, to minimize its longitudinal movement as the shoemoves bodily in applying pressure to said link.

10. A brake comprising a pair of generally semicircular shoes one ofwhich has an anchor at one end and the other of which is unanchored,said shoes being so arranged that the unanchored shoeV is self-actuatingin forward braking, a link connecting the adjacent part of theunanchored shoe to the anchored shoe adjacent said anchor, said linkbeing connected and arranged at such an angle that pressure lengthwiseof the link tends to swing the anchored shoe outwardly about saidanchor, and an applying device acting on the ends of said shoes oppositethe anchor and' which is constructed and arranged to apply a.

balanced spreading pressure on said shoes while the anchored shoe swingson its anchor and the other shoe moves bodily to apply pressure throughsaid link to the anchored shoe. said applying device comprising ahydraulic cylinder and pistons therein having thrust rods connectingthem to the shoes respectively and which pistons are adapted to beforced apart by hydraulic pressure to apply balanced spreading pressureto the shoes,'

at least that one of said thrust rods which acts on the unanchored shoebeing arranged toswing past its center position in moving frombrakereleased to brake-applied position, to minimize its longitudinalmovement as the shoe moves bodily in applying pressure to said link.

LUDGER E. BRJE.

